The present invention is generally directed to micro-instrumentation in the nature of articulating hand held instruments used in micro-surgery, electronic micro-assembly and similar applications of grasping, cutting, punching out, probing and like usages.
Recent developments of miniaturized and other surgical endoscopic instruments have encountered structural limits as the cross-sections become reduced in size. As the tip size of such instruments is reduced, the likelihood of breakage and/or the need to reduce applied force is increased. The high strength and toughness of improved metal alloys have not overcome this problem.
In the typical surgical punch, the two jaw members are adapted to be alternatively opened and closed relative to one another by manipulation of a scissor type handle. These conventional surgical punches utilize an inefficient mechanical design in which the pivot points of the jaws of the punch are subjected to significant stress during use thus shortening the life of the surgical punch. The stress factor is multiplied due to the fact that conventional surgical punches typically use tiny pivot pins to hinge the two jaw members together. Such pivot pins are susceptible to breakage during use, rendering the surgical punches inoperable or worse and result in tiny fragments of sheared metal being deposited in the surgical area. Any number of attempts have been made to solve this breakage problem by increasing the dimensions of selected parts of the surgical punches so as to increase part strength and by attempting to product surgical punches which do not use pivot points. Likewise conventional surgical forceps have the same limitation as surgical punches, e.g. excessive stress at the jaws pivot point leading to early failure or excessive size which hampers their use in micro surgery.
The present invention is directed toward a pin-less pivotable surgical instrument which overcomes the pin shearing problems noted above. A pin-less surgical instrument for knee arthroscopy is disclosed in U.S. Pat. No. 4,712,545. In this instrument the pin type pivot point has been replaced by a moveable jaw member attached to the stationary jaw member by an arcuate lug and groove assembly allowing pivotal movement of the moveable jaw member about an imaginary central axis of the arcuate grooves between an open and closed position. The moveable jaw member is attached to a coupling member so that when the coupling member is moved linearly in a first direction relative to the first stationary jaw member, the second movable jaw member will open away from the first stationary jaw member and when the coupling member is moved linearly in a second opposite direction relative to the first stationary jaw member, the second movable jaw member will close towards the first stationary jaw member.
Another pin-less instrument in the nature of a colposcopic biopsy punch with removable sample basket is shown in U.S. Pat. No. 5,643,307. In this disclosure, a stationary jaw in the form of a die having an open top and bottom is coupled to the distal end of the tube and a movable jaw in the form of a punch is pivotally coupled to the stationary jaw by a tongue and groove arrangement. The punch includes a hollow tube and a push rod which extends through the tube, the proximal end of the push rod being coupled to a lever which is pivotally coupled to the handle. Movement of the lever relative to the handle imparts a reciprocal axial movement to the rod relative to the tube. A stationary jaw is coupled to the distal end of the tube and a movable jaw is coupled to the distal end of the push rod. The movable jaw has a pair of arcuate grooves and the stationary jaw has a pair of arcuate flanges which engage the grooves on the movable jaw. The stationary jaw has an upper opening and a lower opening. The movable jaw is therefore movable into and out of the upper opening of the stationary jaw by action of the lever. The movable jaw has cutting teeth which coact with the inner surface of the upper opening of the stationary jaw when the movable jaw is moved from the open position to the closed position.
Typical pin type pivot instruments are shown by U.S. Pat. Nos. 5,906,630 and 5,603,724. In the ""724 patent an articulating handle of scissors grip construction has an elongated probe extending therefrom with an elongated actuating linkage portion and a tip portion at the probe end distal from the handle. The actuating linkage is a shaft fixedly mounted from the handle, with a longitudinal groove or hole receiving an actuating rod and a tip portion at the distal end of the shaft. The tip portion comprises an assembly of relatively moveable components defined as an inner tip and an outer tip. The inner tip moves while the outer tip is stationary. The tip assembly is operated to excise tissue into pieces and has a pivotal mounting with a fixed shaft extension of the outer tip integrally. The actuating linkage extends from an actuating system in the handle through an elongated channel of the probe and terminates in a connection at the inner tip offset from the pivotal mount to provide a levering articulation motion to the inner tip between upper and lower positions.
Another device using a pivot lug and a rotatable jaw with a pivot seat which wraps around the lug in normal operation is disclosed in U.S. Pat. No. 5,868,786. U.S. Pat. No. 5,908,420 discloses a surgical scissors instrument having a rivet or a screw joining the blade elements.
A tube clamp with a transverse arcuate ridge formed on a stationary member provides a cam for the cam engaging surface of a movable jaw member as is shown in U.S. Pat. No. 4,957,500.
The present pin-less surgical instrument is constructed using cylinders lying in the same plane as fulcrums for the outer tip/inner tip actuator interaction. The actuator has a hollow semi-cylindrical protrusion which mates to a semi-cylindrical recess formed in an inner jaw. A semi-cylindrical protrusion on the inner jaw is positioned concentric to a recess formed in the inner jaw which captures the actuator in a plane perpendicular to their axes. The inner jaw is provided with two centers, one is the center of fulcrum that is mated to the actuator and the other is the pivot, which is mated to the outer jaw. The inner jaw pivot has one protrusion and one recess at this pivot, concentric to each other of conic or cylindrical design. The protrusion on the inner movable jaw pivot is mated with a complementary form in the outer fixed jaw, keeping the inner pivot captured in one direction. The recess of the inner pivot is also mated with a complementary form in the outer jaw, capturing the inner jaw on a radial plane. The surfaces extend radially, perpendicular to the outer jaw and the inner jaw axes to captivate the inner jaw in two directions. The inner jaw/actuator orbits the pivot as the actuator is moved fore and aft by moving the spring biased finger housing against the thumb housing. This movable inner jaw/fixed outer jaw mechanism may be used as a punch, scissor, or grasper, or any other kind of instrument.
The present inventive instrument can be employed in connection with a number of uses for removing, grasping or cutting tissued specimens internally and externally in a medical context.
It is therefore an object of the invention to provide a surgical instrument for internally cutting, grasping, and/or removing tissue, the instrument having movable jaws.
It is an object of the present invention to produce a surgical instrument which is extremely durable and able have jaws which can withstand significant stress during use without failing.
It is another object of the invention to produce a surgical punch which utilizes a novel pivot so as to minimize the stress on its pivot points during use and which does not employ pivot pins in its construction.
It is a further object to produce a surgical instrument which is small in size and able to work well in confined spaces.